> From: Jan Beulich <jbeul...@suse.com>
> Sent: Wednesday, September 15, 2021 5:12 PM
>
> If devices are to be skipped anyway (which is the case in particular for
> host bridges), there's no point complaining about a missing DRHD (and
> hence a missing association with an IOMMU).
>
> While there convert assignments to initializers and constify "drhd"
> local variables.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
Reviewed-by: Kevin Tian <kevin.t...@intel.com>
>
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -1460,14 +1460,10 @@ static int domain_context_unmap(struct d
> static int domain_context_mapping(struct domain *domain, u8 devfn,
> struct pci_dev *pdev)
> {
> - struct acpi_drhd_unit *drhd;
> + const struct acpi_drhd_unit *drhd = acpi_find_matched_drhd_unit(pdev);
> int ret = 0;
> u8 seg = pdev->seg, bus = pdev->bus, secbus;
>
> - drhd = acpi_find_matched_drhd_unit(pdev);
> - if ( !drhd )
> - return -ENODEV;
> -
> /*
> * Generally we assume only devices from one node to get assigned to a
> * given guest. But even if not, by replacing the prior value here we
> @@ -1476,7 +1472,7 @@ static int domain_context_mapping(struct
> * this or other devices may be penalized then, but some would also be
> * if we left other than NUMA_NO_NODE untouched here.
> */
> - if ( drhd->iommu->node != NUMA_NO_NODE )
> + if ( drhd && drhd->iommu->node != NUMA_NO_NODE )
> dom_iommu(domain)->node = drhd->iommu->node;
>
> ASSERT(pcidevs_locked());
> @@ -1497,6 +1493,9 @@ static int domain_context_mapping(struct
> break;
>
> case DEV_TYPE_PCIe_ENDPOINT:
> + if ( !drhd )
> + return -ENODEV;
> +
> if ( iommu_debug )
> printk(VTDPREFIX "%pd:PCIe: map %pp\n",
> domain, &PCI_SBDF3(seg, bus, devfn));
> @@ -1508,6 +1507,9 @@ static int domain_context_mapping(struct
> break;
>
> case DEV_TYPE_PCI:
> + if ( !drhd )
> + return -ENODEV;
> +
> if ( iommu_debug )
> printk(VTDPREFIX "%pd:PCI: map %pp\n",
> domain, &PCI_SBDF3(seg, bus, devfn));
> @@ -1651,17 +1653,12 @@ int domain_context_unmap_one(
> static int domain_context_unmap(struct domain *domain, u8 devfn,
> struct pci_dev *pdev)
> {
> - struct acpi_drhd_unit *drhd;
> - struct vtd_iommu *iommu;
> + const struct acpi_drhd_unit *drhd = acpi_find_matched_drhd_unit(pdev);
> + struct vtd_iommu *iommu = drhd ? drhd->iommu : NULL;
> int ret;
> u8 seg = pdev->seg, bus = pdev->bus, tmp_bus, tmp_devfn, secbus;
> int found = 0;
>
> - drhd = acpi_find_matched_drhd_unit(pdev);
> - if ( !drhd )
> - return -ENODEV;
> - iommu = drhd->iommu;
> -
> switch ( pdev->type )
> {
> case DEV_TYPE_PCI_HOST_BRIDGE:
> @@ -1676,6 +1673,9 @@ static int domain_context_unmap(struct d
> return 0;
>
> case DEV_TYPE_PCIe_ENDPOINT:
> + if ( !iommu )
> + return -ENODEV;
> +
> if ( iommu_debug )
> printk(VTDPREFIX "%pd:PCIe: unmap %pp\n",
> domain, &PCI_SBDF3(seg, bus, devfn));
> @@ -1686,6 +1686,9 @@ static int domain_context_unmap(struct d
> break;
>
> case DEV_TYPE_PCI:
> + if ( !iommu )
> + return -ENODEV;
> +
> if ( iommu_debug )
> printk(VTDPREFIX "%pd:PCI: unmap %pp\n",
> domain, &PCI_SBDF3(seg, bus, devfn));
